Frequency conversion has many uses in optical communication. For example, data can be distributed more efficiently over network channels when reconfigurable optical add-drop multiplexers or similar frequency-converting devices are included in communication links. Likewise, data can be routed more efficiently when network switching hardware is capable of frequency conversion.
Technical approaches to frequency conversion have been implemented in various materials systems. In silicon photonics, for example, direct optical-to-optical frequency conversion has been demonstrated using non-linear processes in silicon. In general, however, such processes are stimulated only with high-power optical input which places them out of reach for at least some applications.
Conversion between optical frequency channels can also be performed in the electronic domain by receiving on a first frequency and retransmitting on a second frequency that may be different from the first. So called optical-electrical-optical (OEO) conversion is known to be a practical solution that can handle high traffic loads and at least moderately high data rates.
However, the conversion to and from the electronic domain limits the ultimately achievable performance by adding latency. OEO conversion also adds hardware and power-consumption overhead.
Hence there remains a need for new approaches to frequency conversion that reduce or eliminate at least some of the disadvantages listed above.